Hydrocracking petroleum and related materials

ABSTRACT

HIGHER MOLECULAR WEIGHT HYDROCARBBONACEOUS MATERIALS CONTAINING POLYNUCLEAR SUBSTANCES, SUCH AS HEAVY PETROLEUM CRUDES AND HIGHER BOILING PETROLEUM FRACTIONS, INCLUDING RESIDUAL FRACTIONS, SHALE OIL, TAR SAND OIL, OIL AND TAR FROM COAL AND COAL ITSELF ARE HYDROCRACKD AT AN ELEVATED TEPERATURE RANGING FROM 250*C. TO 500*C. AND IN THE PRESENCE OF HYDROGEN AT A HPRESSURE OF 200 TO 3000 P.S.I.G., WHILE INTIMATELY MIXED WITH A HOMOGENEOUS CONTINUOUS LIQUID PHASE CATALYST SYSTEM COMPRISING PREDOMINATELY ONE OR MORE PHOSPHORIC ACIDS THERMALLY STABLE UNDER THE HYDROCRACKING CONDITIONS, SUCH AS, PYROPHOSPHORIC ACID AND POLYPHOSPHORIC ACIDS HAVING AN EMPIRICAL ACID AND H2O:P2O5 OF 3 OR LESS, ANDA MINOR PROPORTION, E.G., 10% BY WEIGHT OF CERTAIN METAL POLYHALIDES WHICH ARE ACTIVE HYDROCRACKING CATALYST, E.G., ESPECIALLY ZINC, GALLIUM AND ANTIMONY HALIDES.

U i ed S t P nt O HYDROCRACKING PETROLEUM AND RELATED MATERIALS Milton M. Wald, Houston, Tex assignor to 7, Shell Oil Company No.Dra wing. Filed Apr. 27, 1973, Ser. No. 354,967 Int. Cl. Cg 13/08; 301i 11/78 US, Cl. 208 -108 5 Claims ABSTRACT OF THE DISCLOSURE Higher molecular weight hydrocarbonaceous materials containing polynuclear substances, such as heavy petroleum crudes and higher boiling petroleum fractions, including residual fractions, shaleoil, tar sand oil, oil and tar from coal-and coal itself are hydrocracked at an elevated temperature ranging from 250 C. to 500 C. and in the presence of hydrogen at a pressure of 200 to 3000 p.s.i.g., while intimately mixed with a homogeneous continuous liquid phase catalyst system comprising predominately one or more phosphoric acids thermally stable under the hydrocracking conditions, such as, pyrophosphoric acid and polyphosphoric acids having an empirical ratio of HgOzP o of 3 'or less, and a minor proportion, e.g., 10% by weight of certain metal polyhalides which are active hydrocracking catalysts, e.g., especially zinc, gallium and antimony halides.

' BACKGROUND OFTHE INVENTION Fieldof the Invention This invention relates to the catalytic hydrocracking of higher boiling petroleum oils, shale oil, tar sand oil, coal andoil from coal in the presence of certain metal halide .catalysts. p

v 1 Description of Prior Art Heavypetroleum oils, tar sand oils, shale oil, coal, and coal extracts can be hydrocracked in the presence of various polyvalent metal halides. For example, US. Pats. 3,355,376; 3,371,049; 3,594,329 and 3,625,861 and British Pat: 1,095,851 disclose the use of molten zinc chloride or zinc bromide in hydrocracking coal extracts. US. 3,619,411 and 3,542,665 disclose the use of antimony trichloride, ftribromide or triiodide, bismuth trichloride or tribromide, or-arscnic triiodide, in a continuous liquid phase as catalyst in the hydrocracking of high-boilin hydrocarbons and of coal. US. 3,657,108 and 3,685,962, which are directed to certain methods of regenerating certain spent metal halide catalysts used in hydrocracking, disclose inter alia, the use of zinc chloride, bromide or iodide as liquid phase catalyst for hydrocracking coal. Still further, the addition of certain melting point depressants to molten zinc halide hydrocracking catalysts in hydrocracking heavy oils is disclosed in US. 3,677,932 and also in Netherlands Application 70/ 10318, published Jan. 19, 197l.This"'la tter patent'application also discloses promoting,"the hydrocracking activity of zinc chloride, zinc ,bromide, zinc iodide, antimony chloride, antimony bro- "mide, antimony iodide, bismuth'chloride, bismuth bro- :mide, tin bromide, titanium iodide, arsenic bromide,

arsenic iodide, mercuric bromide, mercuric iodide, and gallium bromide with small amounts of a mineral acid, .preferably corresponding hydrogen halides and pyrophosphoric acid.

There are various advantages obtainable by the use of a large body of a molten metal halide as catalysts and reaction medium for hydrocracking heavy natural oil-containing or oil-precursor material, particularly high polynuclear substances, such as heavy petroleum oil, including crude oils and fractions thereof, shale oils, tar sand oils, coal extracts and coal. On the other hand, there are still many obstacles to commercialization, as will be apparent 3,824,178 Patented July. 16, 1 974 from the many publications in this field, including the aforementioned patents. a

SUMMARY OF THE INVENTION 1 It has now been found that there are still further advantages obtainable in the use of metal halides as hydrocracking catalysts, by the use of the metal halide catalyst dissolved in a relatively large proportion of molten pyrophosphoric acid as a medium for carrying out the hydrocracking. By pyrophosphoric acid as employed in the specification and claims is meant H P O or the equilibrium mixtures of ortho-, pyroand polyphosphoric acids corresponding empirically thereto, or other mixtures of the various phosphoric acids in which the substance is represented by the average formula nH O/P O' wherein n has a positive value 3 or less and the mixture contains a substantial amount of molecular species wherein n is from 1 to 2, inclusive. The compositions and physical properties of such phosphoric acid mixtures are described in Encyclopedia of Chemical Technology, by Kirk and Othmer, 2nd Edition, 1968, vol. 15, pages: 241 and 242.

This invention is based on the discovery that molten pyrophosphoric acid at 250 to 500 C. is uniquely useful as a medium for hydrocracking petroleum oils, shale oils, tar sand oils, coal oils and coal in the presence of an effective, relatively small, amount of the metal halides which are known to be useful hydrocracking catalysts for such materials. It makes it feasible to use a significantly smaller. amount of the metal halide than when using the metal halide also as the reaction medium. Pyrophosphoric acid, as distinguished from sulfuric acid, is not reduced by the hydrogen or hydrocarbonaceous feed or products, nor is it adversely affected by nitrogen, sulfur or oxygen products of the conversion. Thus, if desired, carbonaceous residues can be oxidized (burned) from it without adversely affecting the acid. In addition, pyrophosphoric acid minimizes the reaction of formed ammonia with the metal halide which tends to reduce the activity of the metal halide. Any ammonium phosphates which are formed can be decomposed by heating to liberate ammonia and form phosphoric acid. The present pyrophosphoric acid based system is also advantageous in that any water formed (by hydrogenation of bound oxygen in the feed) will be chemically bound by the pyrophosphoric acid thus minimizing any adverse effect it may have on the metal halide catalyst, such as from hydrolysis. As an essentially nonoxidizing substance, pyrophosphoric acid (as distinguished from sulfuric acid) is compatible with the metal halides, even with metal iodides, without oxidation of the halide to free halogen. It also provides an acidic medium which allows mild cracking while obtaining efficient catalytic hydrogenation of the cracked fragments and other hydrogenable uncracked substances which makes it feasible to use a smaller proportion of a given catalytic metal halide. It also provides a system in which the acid function-catalyzed reactions and the catalyzed hydrogenation can be controlled or regulated with a greater degree of independence from one another. The use of pyrophosphoric acid also provides a system where metal halides which are high-melting or otherwise unsuitable for bulk use, can be utilized as catalysts.

DESCRIPTION OF PREFERRED EMBODIMENTS The invention is practiced by intimately contacting a hydrocarbonaceous feed with hydrogen in a continuousphase molten mixture predominating in pyrophosphoric acid containing a minor proportion of a polyvalent metal halide hydrocracking catalyst under hydrocracking conditions including a temperature in the range from 250 to 500 C. and a pressure of at least 200 p.s.i.g., e.g., from 200 to 3000 p.s.i.g. Hydrocarbonaceous feeds which can g If 1 I 24 173 be suitably processed include, for example, heavy oils and residues, coal, coal extracts, shale oil and the like.

The process can be carried out batchwise or continuously. Contacting of the charge material, catalyst and pyrophosphoric acid medium can be effected by various action on the metal halide and making it possible to utilize asmaller amount of-metal-h'alide than-Would bethe case if the metal halide were employed alone.

The catalytic system in accordance with the invention is a continuous phase liquid "composed predominantely of methods and means, including cocurrent and counter-curpyrophosphoric acid and a minor -proportion; 'ge'nerally ent contacting. The reaction components can be introduced from about 1% by weight to' about 30% 'byweight, preferintothe hydrocracking zone separately, or two or more of ably from 5% to 20% b'y weight, of a'polyvalent metal the reaction components 'can be pre-mixed before subhalide hydrocracking catalyst which is compatible with jecting them to hydrocracking. 10 the pyrophosphoric. acid under hydrocracking conditions.

In one embodiment of the invention the charge ma- It is known that the various metal halides already disclosed terial and hydrogen are continuously delivered to a body to be hydrocracking catalysts differ considerably in cataof the liquid pyrophosphoric acid and metal halide catalyst lytic activity and hydrocracking Selectivity, in melting and the reaction products are continuously withdrawn in point, in viscosity in the molten state at different temperagaseous form and separated from the unconverted hytures and in chemical stability orreactivity in the presence drogen which is recycled to the reaction zone. A portion of various substances which are encountered in hydro of the organic material can also be recycled for further cracking various stocks. These factors require consideraconversions if desired. tion in the selection of the metal halide .andtits concen- Exothermic heat of reaction can be removed as heat of tration and conditions of use. Thus, antimony trichloride vaporization or sensible heat of the gaseous and vaporous is a relatively active cracking catalyst butis rather susstream, and/ or by providing suitable internal or external ceptible to deactivation by water due to hydrolysis. Antiheat exchange between the hot liquid reaction medium mony tribromide is more resistant to deactivation by hyand a suitable coolant to maintain the desired temperature drolysis and more active as a hydrogenation catalyst. Zinc in the reaction zone. iodide, for instance, is fairly resistant to deactivation by A slip-stream can be continuously withdrawn from the water, ammonia and hydrogen sulfide and is highly active reaction zone and filtered or centrifuged to remove solid as a hydrogenation catalyst, but is relatively less active contaminants, such as carbon, ash and metal phosphates, as a cracking catalyst. Such differences influence the vseand the separated liquid phase returned to the reaction lection of metal halide proportions and conversion condizone. Accumulated tarry material in the reaction mixture tions. For example, antimony chloride is active even at may be removed by taking a slip-stream of the reactant temperatures as low as 250 C., while antimony tribromixture and extracting it with a suitable solvent such as a mide is preferably used at 275 to 400 C., especially C to C aromatic hydrocarbon. Alternatively, carboabout 325 to 375 C. Zinc iodide, on the other hand, naceous residue can be burned from solids, which can be can be employed at about 350 to 500 C., preferably at separated by filtration or centrifugation. about 400 to 450 C.

Make-up pyrophosphoric acid and metal halide cata- The extent to which the hydrocracking charge dissolves lyst can be added as required. The make-up acid can be in or reacts with the catalyst system depends in part on provided by adding orthophosphoric acid to the reaction the oxygen, nitrogen and sulfur contents of the charge. zone wherein it loses water at the elevated temperature Petroleum oils low in these elements are relatively insoluto form pyrophosphoric acid, the excess water (regardble resulting in a heterogeneous reaction mixture. On the less of source) being evolved with the volatile reaction other hand, coal, coal extracts and shale oil which conproducts. Alternatively, or simultaneously, phosphorus tain large proportions of such polar atoms are more solu pentoxide can be added which reacts with water derived ble in the highly polar pyrophosphoric acid. from orthophosphoric acid, or uncombined water in the The method of practicing the invention and the results charge, or water resulting from conversion of bound oxyobtained thereby are illustrated by the following examples. gen with hydrogen. Make-up metal halide can be supplied A series of experiments were conducted in which. 20 directly to the reaction zone as such, either as solid or grams of coal (Illinois No. 6, moisture free, 100-200 molten material, or it can be pre-mixed with make-up mesh, 15% ash) was hydrocracked in pyrophosphoric acid pyrophosphoric acid or carbonaceous feed. alone (Experiment 1), in molten SbBr alone (Experiment If desired, hydrogen halide may be added to the system 2) and in pyrophosphoric acid containing variousv metal to minimize any reaction of the metal halide with pyrohalides in accordance with the invention (Experiments phosphoric acid. Some of the metal halides are more re- 3-7). Hydrocracking was effected in each of the experiactive than others with pyrophosphoric acid and also with ments at a temperature of 350 C., a pressure of 1800- other components of the reaction mixture, especially when 2000 p.s.i.g. for a period of one hour, except for Experiwater, ammonia or hydrogen sulfide are produced from ment 1 in which the time was 30 minutes. The composioxygen, nitrogen or sulfur in the hydrocracking charge. tion of the respective catalyst systems and the products An important advantage of the present invention is that obtained from hydrocracking are shown in the following the pyrophosphoric acid reacts with and binds the formed table. The hydrocracked products are reported in units of water and ammonia thereby minimizing their deactivating grams per g. of moisture and ash-free (MAF) coal.

' TABLE A I 1 v r I Experiment 1 2 3 4 5 7 Catalyst type.-. SbBI'a SbBls SbBl: GaBra Gals TiF4 Amount, g 0 10 40 5 8 31 114F201, g..- 107 o 150 150 150 -150 150 Products, g./100 g. MAF coal:

CH3 0 1 T1. 1.2 0.8 1.4 0.5 1.8 0.5 cm. 0.1 1.7 1.9 2.1 1.5 15.1 1. i-oirrm 0.05 4.0 2.5 2.7 2.1 3.6 2.8 10041110 1. 4 0. 3 0. 9 0. 2 0. 5 0. 2 i-on rw 3.7 1.2 1.8 1.3 1.6 1.2 11-00% 0.6 0.1 0.4 0.1 0.1" 0.1 0.11am 0.01 3.3 0.9 1.6 1.0 0.8 0.5 MOP (methyl cyclopentane) 0.01 6.2 1.2 2.1 1.2 0.8 0.3 1H 1H Tr. 15. 8 3. 9 7. 5 6. 3 1. 9 0. 9 691120 to 250 5 17. 0 7. 6 8.0 10. 0 3. a 1.1

Total 0411! to 250 C. boiling range hydrocarbons. 0. 1 52.0 17.7 24.9 22.2 i 12. 7 7.0

Hz consumed, g./l00 g. MAF coal 1.5 9.3 8.5 10.4 8.3 7.7 .7.8 Maximum rate of H1 uptake, p.s.i.g./Inin 4 109 78 96 17 27 20 B Tr= trace.

The results in Experiments 3 and 4 indicate that neither the hydrogenation rate nor the amount of hydrogen uptake decreased greatly for the H P O -SbBr system as compared to the undiluted SbBr system of Experiment 2. While the amount of cracking decreased by two-thirds in Experiment 3, this is considerably less than the decrease in SbBr concentration (a factor of about 15). Moreover, the iso/normal ratios in the C and C products were extremely high, indicating that the cracking which occurred was acid-promoted.

The results of Experiment 5 show that a relatively expensive catalyst such as GaBr can be used in the form of a dilute solution of pyrophosphoric acid and still main tain reasonably good activity. This illustrates the advantage of the present invention in using an active but expensive catalyst under conditions such that overall catalyst costs will be low.

A further advantage of the use of pyrophosphoric acid as the reaction medium is demonstrated in Experiment 7. The TiF catalyst employed in this experiment is very difficult to use in bulk in that it sublimes at 284 C. without melting. However, this catalyst can be efiicaciously employed when dissolved in pyrophosphoric acid as shown in Experiment 7, although the hydrogenation and cracking rates are lower than obtained with the other metal catalysts.

What is claimed is:

1. In a process for hydrocracking higher molecular weight hydrocarbonaceous materials containing polynuclear substances by contacting said materials in the presence of hydrogen with a continuous liquid phase catalyst system containing a polyvalent metal halide as the essential hydrocracking catalyst under hydrocracking conditions including a temperature in the range of 250 C. to 500 C. and a pressure of from 200 to 3000 p.s.i.g., the improvement which comprises providing the metal halide catalyst in homogeneous liquid phase mixture with a major proportion of at least by weight of pyrophosphoric acid.

2. The process of claim 1 wherein the catalyst system is essentially 5-30% antimony t rihalide in homogeneous liquid phase mixture with at least 70% by weight of pyrophosphoric acid. 5

3. The process of claim 2 wherein the antimony trihalide is antimony tribromide.

4. The process of claim 1 wherein the catalyst system is essentially 5-30% by weight zinc halide in homogeneous liquid phase mixture with at least 70% by weight pyrophosphoric acid.

5. The process of claim 4 wherein the zinc halide is zinc iodide.

References Cited UNITED STATES PATENTS 2,075,101 3/1937 Dreyfus 208-10 2,100,352 11/1937 Pier et a1 208-10 2,191,156 2/1940 Pier et al. 208-10 3,619,411 11/1971 Wald 208-108 3,371,049 2/ 1968 Gorin et a1. 252-413 3,652,446 3/1972 Dengler et a1. 208-10 3,745,108 7/ 1973 Schuman et a1. 208-10 3,764,515 10/1973 Kiovsky 208-10 FOREIGN PATENTS 7,010,318 1/ 1971 Netherlands 208-10 2,034,693 2/1971 Germany 208-10 DELBERT E. GANTZ, Primary Examiner G. E. SCHMITKONS, Assistant Examiner US. Cl. X.R. 208-10; 252-435 

